Method of making silicon steel



Patented May 1925.

VERE B. BBOWNE, OF BRACKENBIDGE, PENNSYLVANIA.

METHOD OF MAKING SILICON STEEL No Drawing.

Y '0 all wlwm it may concern;

Be it, known that I, VERE, B. BRowNn, a

- citizen of theUnited States, and a resident of Brackenridge, in the county of Allegheny and the State of Pennsylvania, have made a new and useful Invention in Methods of Making Silicon Steehof which the followis a specification. his invention relates to silicon steel and a method of making the same.

An object of this invention is to provide a method by means of which ductile, homogeneous silicon steel of any desired silicon content free from inclusions and low in carbon may be readily made.

In building up certain laminated structures of electrical apparatus, silicon steel in the form of sheets is now commonly used. The presence of the silicon has a marked influence on the magnetic and electrical qualities of the steel particularly in apparatus operating at high densities.

As the presence of silicon in the steel im: pairs its capacity for being rolled or otherwise worked, it is now common to add manganese to silicon steel to improve its workability. It is customary to make the magnanese addition in the form of ferro-manganese or spiegeleisen but the addition of manganese in this manner necessarily increases the carbon content ofthe finished steel to such an extent that its electrical properties are unpaired.

A further object of this invention is to provide a method of making iron silicon manganese alloys having a carbon content suflicient'ly low as not to impair its value for use in electrical apparatus requiring high magnetic permeability and low hysteresis.

In making silicon steel, the preferred method of obtaining the necessary silicon content is to place the desired amount of ferro-silicon which has first been raised to red heat, in the ladle and to add to this, the molten steel.

r The method by which I attain the objects of this invention consists in reducing manganese from manganese ore in the ladle in the presence of the ferro-silicon. The amount of manganese ore (manganese oxide) must be inexcess of the theoretical amount necessary to give the desired manganese content to the finished steel. It is preferable, but not necessary, to mix a small amount of fluorspar with the manganeseore before the same is added to the ladle. Since Application filed May 15, 1928.

Serial No. 639,195.

r the reaction of reduction will not be com plete, there will remain,gth la@a small quantity of free manganese oxide which will combine with the silica silicate of manganese. ilicateof mange-- nese has a relatively low fusing point and in the presence of the fiuorspar forms a solvent. for any refractory material entrapped in the steel. I

The amount of manganeseore added in the ladle will depend upon the percentage ofmanganese desired in the finished steel and the quality of the ore used, but it must always be in excess of the theoretical amount in order to obtainthe desired manganese content in the finished steel. I find that it is preferable to place the ferro-sili con in the ladle after the same is brought to a redheat andto place the manganese ore in the ladlebefore-the molten steel is tapped into the same. When the manganese ore is added at this time, the silicon present combines with the oxygen in the manganese ore to form' silica and manga-v nese metal is precipitated and alloys with the steel.

As this reaction. is'not complete under of manganese oxide remaining in theladle.

This serves as a cleanser by combining with such conditions, there-is always an excess silicate of alumina and l and alumina which may be entrappedin the molten steel.

These silicates are thus eliminated by direct combination and by mechanical absorption and separation. 7

Having thus described my invention, what I claim is a 1. The method of adding manganese to steel, which consists in directly reducingmanganese from manganese ore by bringing together in the ladle manganese ore and molten steel.

2. he method, which consists in directly ledL -ng manganese from manganese ore by bringing together in the ladle manganese ore and molten steel, whereby'manganese is added to the steel, and refractory impurities such as alumina and silica are removed by cL. ibining with manganese oxresent forming a id e tojiform'sil'icates of manganese and alui I 'mmum having relatively low fusinggtemper atures and are eliminated by direct combination and by mechanical absorpt on and separation. 3. The method of m aking' an iron silicon manganese alloy which consistsi n directly reducin'g'" manganese from manganese ore- 1923.

in the ladle in the presence and ferro-silicon.

of molten steel 4. The method of making aniron silicon manganese alloy ,low in carbon which eon sists in mixing ferro-silionand manganese oxide with imoltensteelin vthe ladle before teeming i V .4

In testimony whereof, I havehereunto subscribed my name this 8th .day 'ofMay',

VE QBROWNE, 

